Reliability is the probability of fault-free operation of software over a particular time limit. Most of the work done in this area generally focus on finding the reliability at the later stage, which can answer what is the reliability of the system, but it can’t ensure what the reliability should be. Finding reliability is a major task for providing the user appropriate level of services with less fault-rate, so it is mandatory to predict the reliability before implementation and let the system to be modeled accordingly to achieve certain predetermined reliability. This paper focuses on the above mentioned requirement. In this paper we have generated the use case diagram and component diagram for each use cases. The use case diagram represents the sequence of operations and the component diagram represents the involvement of the components to give rise to particular use case. A fault tree is generated that is used to find out the fault rate associated with each component of the software system that leads to failure in the upper-level operation.